The present invention relates to the terminal fitting structure of a circuit switching device (service plug) for opening an electric circuit and cutting off the current of the circuit, and particularly to enhancing operability in attaching or detaching a plug body provided with short-circuiting terminals to/from circuit terminals.
In the switchboard of a high-voltage circuit and others, there is a circuit switching device used so that an operator is prevented from getting electric shock by detaching a plug provided to the switchboard from a terminal fixed in the body of the switchboard and cutting off the current of the circuit when the operator opens the cover of the switchboard.
Recently, attention is paid to an electric automobile as a pollution-free vehicle which does not exhaust exhaust gas. In the above electric automobile, since a high-voltage circuit for driving a motor is also provided, the current of the circuit is required to be cut off for the same reason as the above in maintenance service. At such a request, a circuit switching device (connector device) which is used in a conventional type electric automobile and automatically opens a high-voltage circuit stored inside a switchboard when the cover of the switchboard is opened, is disclosed in Japanese Patent Unexamined Publication No. Hei. 6-310227.
FIG. 6 is a perspective view showing a conventional connector and FIG. 7 is a sectional view showing a process in which the cover of the conventional connector is shut. A female connector 3 is fixed inside a box-shaped housing 1 the top which is open and can be connected to external high-voltage cables 5a and 5b via each connector terminal 6. A cover 7 for opening or closing an opening is provided to the housing 1 and is turned with a turning shaft 9 as the center. A guide 11 is provided to the cover 7 and holds a male connector 13 and a guide member 15 so that they can be moved in the direction perpendicular to the turning shaft 9. A spring 17 shown in FIG. 7 is arranged between the internal wall of the guide 11 and the male connector 13 and presses the male connector 13 and the guide member 15 in the direction in which they approach the turning shaft 9.
In a connector device 19 constituted as described above, when the cover 7 is shut, the male connector 13 approaches the female connector 3, drawing an arc-shaped locus with the turning shaft 9 as the center. The male connector 13 is moved in the direction in which it is parted from the turning shaft 9 against pressure by the spring 17 when the guide member 15 comes in contact with an internal wall 20a of a guide hole 20 in a process in which the male connector is fitted into the female connector 3, is again moved by pressure by the spring 17 in the direction in which the male connector approaches the turning shaft 9, is fitted in the female connector 3, absorbing dislocation caused by the arc-shaped locus in the fitting process, and electrifies the high-voltage cables 5a and 5b.
In the meantime, when the cover 7 is opened, the male connector 13 is detached from the female connector 3, being moved in the direction in which the male connector again approaches and is parted from the turning shaft 9, opens a high-voltage circuit between the high-voltage cables 5a and 5b, and as a result, can automatically cut off the current of the circuit.
However, in the above conventional connector, since the male connector 13 is provided on the cover 7, the male connector 13 is detached or fitted from/in the female connector 3 by opening or shutting the cover 7, and a high-voltage circuit is automatically opened or closed, if the cover is shut by mistake during maintenance, the high-voltage circuit is closed, the current of the circuit flows, and an operator may get electric shock. Therefore, it is desirable to construct the circuit switching device such that a plug body provided with short-circuiting terminals inside can be completely separated from the circuit housing.
In the above circuit switching device, since a handle such as a lever is not provided to the cover 7, an operation for opening or closing is difficult. In the meantime, if a lever is protruded from the cover 7, it becomes an obstacle in an electric automobile and others the space of which is limited. Even if a lever folded by turning, is provided, if pushing force or tensile force by the lever does not operate on the fitting center of a terminal, there occurs a problem that a moment is generated, the operating force is decreased, distortion is caused between the terminals to be fitted, and operability is deteriorated.